Method of sealing a container



@c'if24, 1967 w, my 'rB'i'ERN/XLE 3133438358 METHOD OF SEF-LING A 'IONTLTNER Filed June 15, 1956 4 Sheets-$hee 1 INVENTOR. MARTIN M. STERNAUATTORNEY v 1967 M. M. STERNAU METHOD OF SEALING A CONTAINER 4Sheets-Sheet 2 Filed June 15, 1956 FIG. 7A

"qgmaaea -INVENTOR. MARTIN M. STERNAU ATTORNEY METHOD OF SEALING ACONTAINER 4 Sheets-Sheet Filed June 15, 1956 INVENTOR. MARTlN M. STERNAU ATTORNEY Oct. 24, 1967 M M. STERNAU 3 3 METHOD OF SEALING ACONTAINER Filed June 15, 1956 4 Sheets-Sheet 4 35/ I l 3 s INVENTOR.

MARTIN M. STERNAU ATTORNEY United States Patent 3,348,358 METHOD OFSEALING A CONTAINER Martin M. Sternau, Flushing, N.Y., assignor, bymesne assignments, to W. R. Grace & (30., Duncan, 8.0, a corporation ofConnecticut Filed June 15, 1956, Ser. No. 591,628 9 Claims. (Cl. 53-42)One of the objects of my invention is to provide a closure which is aninexpensive, simple hermetic seal for a container irrespective ofwhether the container is made of paper, plastic, aluminum, steel, etc.

Another object of my invention is to provide a hermetic seal for acontainer irrespective of whether the container is made of paper,plastic, glass, aluminum, steel, etc.

Another object of my invention is to provide a 2-part closure comprisingan inner sealing closure and an outer protective closure.

Another object of my invention is to provide a closure formed from atransparent oriented plastic sheet alone, or from two dissimilarmaterials, the inner component being formed of a transparent orientedplastic sheet and the outer component being formed of a semirigid,moldable material.

Another object of my invention is to provide a sealing closure that willpermit removal and replacement of the outer cover whereby inspection ofthe contents of the container may be had without breaking the seal ofthe inner component, thereby eliminating the danger of contamination.

Another object of my invention is to provide a closure which willenclose the rim of the container in a sanitary manner.

Another object of my invention is to provide a closure which will reducethe cost of manufacture of the container by reducing the amount ofcontainer material required.

One of the aspects of this invention is a closure made of flexible andmoldable material, and particularly a closure having a beaded andexpansible rim.

One of the objects of my invention is to make an improved closure, .withor without an inside cover of plastic material, in which the rim ispleated before being formed or rolled in such a manner that expansionand contraction at. the rim area may occur to receive and to hold theslightly larger bead on the mouth of a container by locking the rim ofthe closure below the bead of the container.

Another object of my invention is to provide a method and apparatus forforming the cover and for positioning the cover on a container.

Anotherobejct of my invention is to provide a method of holding orretaining transparent, oriented plastic sheet material during conversioninto a hermetic sealing cover on a container.

Another object of my invention is to provide a method of sealing aplastic sheet closure on a container.

Another object of my invention is to provide a method of manufacturing ahermetically sealing cover from basic raw sheet materials directly uponthe container upon which it shall be used and at the time of closure ofthe container, using the container as the male forming component of theclosure.

Another object of my invention is to provide a heat sealing closure fora container.

Another object of my invention is to provide a construction of materialsthat may be manufactured into a hermetic closure prior to or duringapplication on the container.

A still further object of my invention is to provide a cord to tear openeither the plastic filmor 'both covers when a two part closure is used.

A still further object of my invention is to provide ICE additionalsealing means in case additional sealing insurance is desirable.

With the foregoing and other objects in view as will appear from areading of the following specification and claims, the invention residesin the novel arrangement and combination of parts and in the details ofconstruction and process of manufacture hereinafter described andclaimed, it being understood that changes in the precise embodiment ofthe invention may be made within the scope of what is claimed withoutdeparting from the spirit of the invention. It will be furtherunderstood that the invention is susceptible of embodiment in many andvarious forms, some of which are illustrated in the accompanyingdrawing, and that the structural details or particular steps of themethod herein set forth may be varied to suit particular purposes andstill remain within the inventive concept.

Referring briefly to the figures:

FIG. 1 illustrates a 2-ply closure in a vertical sectional view;

FIG. 2 shows a 2-ply closure according to the invention ready for use;

FIGS. 3, 4, 5 and 6 show various types of protective covers which shieldthe inside sealing cover on difierent type containers;

FIGS. 7 and 7a show another type closure before and after crimping isaccomplished;

FIGS. 8 and 8a show a similar type of 2-part closure before and afterbeading same together with container;

FIG. 9 shows a single cover which has an opening string beneath it;

FIG. 10 shows additional sealing cement beneath the sealing cover;

FIG. 11 illustrates a forming apparatus with curling rings, a male diehaving a resilient ring in it (which may be omitted) to form aperipheral crease or indentation in the sidewall of the closure and aperipheral groove in the female die for providing said indentation;

FIG. 11w shows a capping and sealing tool for snapping the cover over areceptacle and retaining it while heat is applied to seal the innercover;

FIG. 12 shows a suction head which carries the shrinkable film and sealsit to the receptacle;

FIG. 13 shows a different type apparatus for applying heat to theclosure to seal the inner layer after crimping;

FIG. 14 illustrates a 2-ply closure with an inspection hole in the outerlayer;

FIG. 15 illustrates a straight sided container 32 with a modified 2-partclosure formed from two rolls.

This invention is for a system providing a closure of circular,rectangular, hexagonal, or any other shape for a receptacle. The closureconsists of a combination, lamination or otherwise physically held inapproximately uniform parallel position (of an inner or underside coverof a shrinkable and clear, translucent, or opaque, film or sheet, and anouter cover of a moldable, rigid or semirigid, and clear, translucent,or opaque material, such as, aluminum, paper, plastic, glass, steel,etc. The inner cover is to provide a seal for the container on which theclosure is used, and the outer cover is to provide a mold or ret ainingform or device for the former during the sealing operation and toprovide an ultimate protecting cover for the former and for thecontainer upon which this closure is used.

As one example, the outer cover of the closure possesses a peripheralflange formed prior to, or during, the operation aflixing the closurecover or covers to the container and having applied at its outer rim oredge means wherein both components of the closure are rolled, curled,bent or otherwise temporarily or permanently held together so that theinner component of the closure is held or retained by or within the rimof the outer component. The securing together of the two covers orcomponents is done prior to, during, or after the sealing operation.

There are several possibilities by which a closure as outlined above maybe put into a practical form: I

(1) A closure may be made as shown in FIG. 2 comprising plies of adissimilar material, the inner layer consisting of a transparent filmshrinkable under heat application, the outer layer made of aluminumsheet or any other moldable material. Both components are formed into acover having, as one example, a circular top portion and an integralperipheral flange and a beaded rim. If this type closure is snapped ontoa container with a beaded or a plain edge, the bead of the closure willbe locked circumferentially below the rim of the container. When heat isapplied selectively to the rim of the closure or the container, thefollowing takes place:

(a) The film will shrink a maximum distance circumferentially around therim of the container with the result that:

(b) It will pull the beaded rim of the outer layer of the closuretighter around the circumference below the head of the container. Thisoccurs because both elements are engaged thereby making the outer covertighter on the container.

(c) The shrunken film will conform to the shape and irregularities ofthe container rim creating an additional seal around the rim of thecontainer.

, (d) Due to thi local, circumferential shrinkage the remainder of thefilm under the outer layer will be pulled tightly across the mouth ofthe container, still further improving the seal at the mouth of thecontainer.

(e) Should wax or a heat sensitive cement be applied to the rim of thecontainer before attaching the cover, an additional seal will be formedat the time of heat application.

Similarly, the above function takes place with different type closuresused on different type containers.

(2) A cover may be made as shown in FIG. 1, for ex ample. This cover hasa peripheral crease to facilitate the formation of a peripheral bulge(FIG. 2) before the closure is snapped onto the container. A closure asshown in FIG. 1 has the advantage of economical space saving stackingfor packaging.

(3) A closure may be made using an outer single-ply cover of aluminum,or paper, etc. as a retainer for a shrinkable plastic sheet, which issubstantially larger than the mouth of the container. The plastic sheetis placed on top of the container, and the cover snapped onto thecontainer. This will create the essential condition that the film isheld fiat across the mouth of the container, while the rim of the filmis arranged around the rim of the container in pleats protruding beyondthe outer cover. Thus, when heat is applied to the rim, the protrudingfilm will shrink, conforming to the shape of the rim of the containerand forming therewith a tight seal around said rim, while the remainderof the film is pulled tightly across the mouth of the container. Thisthird method has the advantage that the outer cover can be removedwithout disturbing the seal of the film portion of the closure. Thisprocess has the additional advantage that the outer cover can berepeatedly taken off and snapped back onto the container without losingits original efliciency of snapping onto the container, and lockingbelow its rim due to its expandable pleated rim.

(4) A closure may be made as shown generally in FIG. 1 or FIG. 2 butwith the outer cover 30 having a hole 31 in the center for visualinspection through the transparent inner cover 5 without removing thecover or breaking the seal, all as shown specifically in FIG. 14.

It is not necessary, but if desired, as shown in FIG. a wax cement, etc.14 may be applied prior to or during the sealing operation at the pointof seal upon the container, and said material will adhere to theshrinking or shrunken film during the sealing operation and therebyprovide double protection against leakage. Also, any of the covers mayhave incorporated a means of tearing, or otherwise removing said sealedfilm cover by means of a string, band, etc. 13 by having this deviceincorporated into the cover construction prior to or during the sealingoperation as shown in FIG. 9.

Since the rim of the plastic film portion is rolled into the rim of thealuminum portion of the closure, it is locked and retained by thealuminum portion of the cover. Consequently, when this cover as snappedon an aluminum container, and heat is selectively and circumferentiallyapplied to the cover, the plastic film portion will shrink a maximumcircumferentially around the rim of the container at the point of theapplication of heat due to its inherent characteristics. Thus it willtake the shape and configuration of the rim of the circular,rectangular, or other shape of the container, and create therewithv aleakproof seal around the rim of the container.

It is a novel feature to place a sheet of shrinkable, oriented plasticfilm on top of a paper, plastic or aluminum sheet or foil container tohold it by any outer cover and by subjecting it selectively to heat, toshrink it around the mouth of the closure, thereby forming a leakproofseal.

FIG. 1 shows an outside cover somewhat similar to the cap illustrated inmy previous invention, Ser No. 289,032, Patent No. 2,756,921, grantedJuly 31, 1956, upon which this is, in certain respects, an improvement.Among other things, the invention as illustrated in FIG. 1 is directedto a more or less loose roll or double fold of the rim whereby thepleated area in the rim is freely able to expand and contract as thecover is slipped over the mouth of the container. Also, a thin plasticfilm cover may be applied, if desired, in connection with the outercover.

Numeral 1 represents the rigid cover made of flexible, moldablematerial, such as aluminum, paper or plastic, While 2 indicates thecrease formed in the flange of the cover and 3 indicates the more orless loose roll of the rim. Obviously, edge 3 may be formed with adouble fold rather than a loose roll, the main consideration being thatthe edge be expansible and lock beneath the edge of the container.Numeral 4 indicates the pleats which are formed in the flange of thecover and 5, if a liner is used, illustrates such liner or inside cover.

Upon the application of pressure as the cap is being secured to thecontainer, due to the crease, the bulge will be formed, as clearlyindicated in FIG. 2.

FIGS. 3 to 6 indicate various types of closures, in which numeral 5illustrates the inside plastic cover with various types of outsideprotective covers such as cover 1 in FIG. 3; cover 6 in FIG. 4; cover 7in FIG. 5, and cover 8 with a central depressed portion in FIG. 6. Thesecovers may be placed on dissimilar type containers 9, 29, etc. Clearly,the two covers may be laid flat over a straight sided container as shownin FIG. 15.

FIGS. 7 and 7:: illustrate a plastic film cover 5 and protective cover10 placed over container 9. Subsequently these covers are crimped aroundto make a tight closure, as illustrated in FIG. 7a, and heat is thenapplied selectively around the rim.

FIGS. 8 and 8a depict a straight edge container 12 having an insideplastic cover 5 and a recessed closure 11 applied over the top of theinside cover, both before and after the rolling, beading or crimping andheat sealing operation.

FIG. 9 shows the container 9, in which only a l-part closure ortransparent plasticcover 5 is applied to the container, and securedthereto is an opening string 13. This type closure is ideally suited, ina circular container, for bakery goods, such as, cakes and pastries or,in a rectangular package, for food products.

FIG. 10 shows a plastic sheet 5 secured to container 9 with additionalsealing cement 14 at various spots, or completely around the edge of therim. Obviously, the

opening means of FIG. 9 could be applied to the closure FIG. 10 or anyother figures, with or without the outside cover, and likewise, thesealing cement 14 of FIG. 10 could be applied to the otherconstructions.

FIGS. 11, 11a, 12 and 13 illustrate the dies which can be used in makingthe cover and in sealing the container as set forth in applicantsinvention.

FIG. 11 shows a male die 15 having a resilient ring 16 therein. Femaledie 17 has a groove 18 opposite the resilient ring 16 in the male die.Upon pressure being applied by the male or forcing die, the closurebeing formed is forced into the groove by means of the elasticity of theresilient material to form the crease. At the same time, curling rings19 and 20 form the rim of the cover. The resilient ring 16 may beomitted if desired, but then a less pronounced crease will be formed.

The 2-part closure is then picked up by the suction in the capping andsealing tool 21 (FIG. 11a) which has a suction line 22 therein, and asthe container 9 is snapped beneath the formed cap, or vice versa, heatis applied to the rim of the closure through apertures 23a. The heat maybe applied by hot air, hot water, steam, electricity, or even by an openflame. The application of heat will cause the oriented plastic film toshrink around the rim of the container and therefore form a tight,leakproof seal. Tools 21, 23 are of asbestos, hard rubber, etc., eitherentirely, or around heat passageways.

FIG. 12 shows a different type of suction sealing disc 23 having suctionlines and positioning line 24 in it. While FIG. 12 shows only ashrinkable film being placed over the receptacle and sealed by means ofhot air or steam passing through apertures 25, it is clear that a Z-partclosure could be just as easily used.

FIG. 13 shows a different type of crimping and sealing device 26 havinghot air apertures 27 therein and a holddown plate 28.

FIG. 14 illustrates my invention with a different type closure having abody portion 30 with an opening 31 in the center by means of which thecontents of the container may be seen through the plastic inner cover 5.

FIG. 15 shows a roll 36 of outer protective material 35, and a roll 34of inner transparent material 3-3, both of which are positioned over astraight, non-beaded, circular or rectangular container 32. A shears 37cuts both layers of the material in cooperation with a heat sealing andcrimping device; for example, as shown in FIG. 11a. The shears may becombined with the heat sealing and crimping device if desired so as toprovide a one-motion operation for sealing a container from basic sheetmaterial. Similarly, the two components of the closure may be fed fromone roll, having been re-rolled onto the single roll in a prioroperation.

It is therefore clearly apparent that I have invented a sanitary coverwhich will decrease the quantity of, for example, aluminum, to pack acertain amount of goods. This is true because in the ordinary insidefriction closure sealed on an inwardly extending rib from the top,approximately 8% of the normal capacity of the container is wasted. Withthis flexible, transparent film across the very top, the entirecontainer may be utilized. This is particularly so in aluminum packagingwhich is becoming so common today. Also connected with this sanitaryfeature is the sales appeal of transparent closures in which the publicdemands to see that which they are purchasing, especially in the foodfield.

My invention may be used either as a l-stage or a 2- stage operation. Inother words, the transparent film may be used alone or the outside covermay be used alone, or if the combination closure is used, the insidecover may be first applied and then the outside cover applied later, orin a more practical Way, the two covers may be formed together andapplied as a laminated unitary closure.

It is therefore seen that there has been provided a leakproof andmoisture proof closure which is easy to manufacture and is inexpensive.While the invention is particularly adapted for outside covers andcontainers of aluminum, the invention is equally effective for paper,plastic, steel, etc.

Other modifications of the principal items of this invention are clearlyapparent, and I do not desire to be limited in my invention except asset forth in the claims.

A continuation-in-part application covering among others the subjectmatter of original claims 1-14, i.e., article claims, was filed Apr. 16,1957 as application Ser. No. 653,227, now abandoned.

What is claimed is:

1. A method for capping and sealing a closure having a protective coverand a heat shrinkable film using a capping and sealing die, comprisingthe steps of holding the closure by suctionin the capping die,subsequently snapping the closure onto the receptacle, and retaining theclosure ontop of the receptacle while directing a heating agent throughnozzles toward the rim of the closure and thus shrinking the film andclosing and hermetically sealing the receptacle.

2. A method for hermetically sealing a container comprising the steps ofdraping a fragile, transparent, thin, flexible oriented plastic filmcover over an aluminum container to be sealed, placing an opaqueprotective aluminum cover over said fragile plastic cover, crimping theedges of both covers and at the same time applying heat to the edges ofsaid covers whereby the oriented plastic film will contract and form anairtight cover for the container.

3. A method for forming a closure and sealing a container in acontinuous operation, utilizing a roll of transparent shrinkable film,and a second roll of moldable, flexible material, comprising the stepsof unrolling and superimposing webs from both rolls of said materialover a container to be closed, positioning said transparent shrinkableweb intermediate the container and the molda'ble web, shearing apredetermined length from said superimposed webs of material to drapeover said container and subsequently capping said container by crimpingsaid length into a closure and selectively heat sealing said shrinkablecomponent of said closure to form an airtight closure.

4. A method of providing a two part closure for a container, saidclosure comprising an inner sealing cover for the container and an outerprotective cover for the sealing cover, said method comprising the stepsof placing a sheet of transparent, heat shrinkable, oriented, plasticfilm upon the mouth of a container, said sheet being susbtantiallylarger than the mouth of the container, placing an outer cover of adifferent material upon said sheet to retain said sheet across the mouthof the container and to cause the peripheral portion of said sheet todrape substantially downward around the rim of the container, andapplying heat to said sheet to obtain shrinkage of said sheet andformation of a sealing cover, said shrinkage locking said sealing coverbelow the rim of the container to render said sealing cover capable ofretaining its seal when the outer cover is removed.

5. A method of sealing a container comprising the steps of applying tosaid container a two-ply cover having one ply of heat shrinkableoriented film and one ply of a dissimilar material, said film and saidmaterial being previously joined at their rim areas, and applying heatto said cover to obtain shrinkage of the film and sealing of thecontainer.

6. A method of sealing a container having an opening at its top forminga mouth comprising the steps of placing a sheet of fragile, transparent,thin, flexible, heat shrinkable, oriented plastic film on top of acontainer to be sealed and over said month, said sheet beingsubstantially larger than the mouth of the container and extendingbeyond said mouth circumferentially, arranging the edge portion of thefilm which extends beyond said mouth into depending pleats, retainingsaid sheet in a position above and across the mouth of the container,

7 and applying heat to said pleats to obtain shrinkage of sheet beingsubstantially larger than the opening of the mouth of the container,arranging the edge portion of said sheet into depending pleats,retaining said sheet over the mouth of the container and applyingsuflicient heat to said pleats to obtain shrinkage of said pleats toengage and seal the container and cause the resultant radial compressiveforces at the rim area of the container to impart additional strengthand rigidity to the rim area of the container. 7

8. A method of sealing a container comprising the steps of placing asheet of heat shrinkable plastic film over the mouth of a container,said sheet being substantially larger than the opening of the mouth ofsaid container, gathering the edge portion of said film into dependingpleats, shielding said sheet across the mouth of said container andsimultaneously applying heat to the rim area of said sheet to shrinksaid sheet selectively primarily at its rim area to seal the container.

9. A method of sealing a container comprising the steps of placing asheet of heat shrinkable, oriented, plastic film over the mouth of acontainer, said sheet being substantially larger than the opening of themouth of the container, arranging the rim of said sheet into downwardlydepending pleats, retaining said sheet upon said mouth of said containerby placing a shield of rigid material above said sheet and in proximityto said sheet across the mouth of the container leaving said pleats inexposed position, and applying heat to at least the rim area of saidsheet to obtain shrinkage of said sheet at said rim area, said shrinkagecausing said sheet to form a cover and to seal the container.

References Cited UNITED STATES PATENTS 825,116 7/ 1906 Engles 53-391,271,944 7/ 1918 Rosengren 53-297 1,746,669 2/1930 Moore 229-431,891,866 12/1932 Bodor 93-365 1,952,530 3/ 1934 Bedworth 93-3652,141,833 12/1938 Young 53-42 X 2,263,152 11/1941 Wilcox 53-287 X2,409,788 10/1946 Osborne 53-42 2,447,855 8/ 1948 Goodwin et al 93-132,447,983 8/1948 Little 215-38 2,595,046 4/ 1952 Amberg 93-13 2,608,3347/1952 Knocke. 2,707,588 5/1955 Amberg 229-43 2,732,116 1/ 1956 Merrill53-42 TRAVIS S. MCGEHEE, Primary Examiner.

EARLE DRUMMOND, RICHARD J. HOFFMAN, ROBERT A. LEIGHEY, ROBERT E.PULFREY, THERON E. CONDON, Examiners.

8. A METHOD OF SEALING A CONTAINER COMPRISING THE STEPS OF PLACING ASHEET OF HEAT SHRINKABLE PLASTIC FILM OVER THE MOUTH OF A CONTAINER,SAID SHEET BEING SUBSTANTIALLY LARGER THAN THE OPENING OF THE MOUTH OFSAID CONTAINER, GATHERING THE EDGE PORTION OF SAID FILM INTO DEPENDINGPLEATS, SHIELDING SAID SHEET ACROSS THE MOUTH OF SAID CONTAINER ANDSIMULTANEOUSLY APPLYING HEAT TO THE RIM AREA OF SAID SHEET TO SHRINKSAID SHEET SELECTIVELY PRIMARILY AT ITS RIM AREA TO SEAL THE CONTAINER.